Adaptations to use the internal MiniZip fork instead of libzip, with zlib, and to compile under OSX 10.6.8 x86_64.
Creation of app bundle with icon file for Mac OSX in RELEASE mode.
Merge against current upstream master
CMake 2.6 build possible
Merge branch 'master' of https://github.com/ChristianFrisson/Drawpile into ChristianFrisson-master